"We're more concerned about him as the individual and he's more concerned about the team and not letting the team down," Rennie told the New Zealand media.

"So ultimately it's best that he gets this done and then we get an all clear for him to return.

"Certainly the specialists and everyone are confident he will make a good return."

Rennie says the condition has been controlled by medication and while Fruean had been coping well, it flared up against the Highlanders a fortnight ago.

The Chiefs, who are unbeaten after three games this season and lead the New Zealand conference, will also travel to face Australia's Western Force and South Africa's Bulls and Cheetahs without wing James Lowe and centre Charlie Ngatai.

All Black flank Sam Cane, who sustained a knee injury in a pre-season clash with the Blues, has returned to join the 27-man travelling squad.

During the Chiefs' 36-20 win over the Stormers at Waikato Stadium last Friday Ngatai injured his calf muscle and will be out for four to six weeks.

Lowe damaged his MCL knee ligament and will also remain back in New Zealand with an expected recovery time of four to six weeks.

Ben Afeaki and Augustine Pulu also moved off the injured list to join the travelling group and will be joined by wider training squad members Brad Webber and Anton Lienert-Brown and Jordan Payne.